A direct variation between two variables "x" and "y" is given by the following formula:
y = kx
We can rewrite the given expression 8y-7x=0 to get an equation of the form y = kx like this:
8y - 7x = 0
8y - 7x + 7x = 0 + 7x
8y = 7x
8y/8 = 7x/8
y = 7/8x
The number that is being multiplied by x should be the constant of variation k, then in this case, the constant of variation equals 7/8